Consider the following.

f$($x$,$ y$)=$ x$2$ey$,$ P$(7,0),$ u $=$

$15$

$(3$i $4$j$)$

$($a$)$

Find the gradient of f$.$

$$f$($x$,$ y$)=$

$($b$)$

Evaluate the gradient at the point P$.$

$$f$(7,0)=$

$($c$)$

Find the rate of change of f at P in the direction of the vector u$.$

Duf$(7,0)=$